Abstract
Kinases are essential cell signaling enzymes that phosphorylate protein substrates using ATP as the universal cosubstrate. A wide variety of ATP analogs have been used in kinase research, although the studies are limited by the cell impermeability of ATP. Here we describe the use of the cationic polymer deacetylated chitosan to permeabilize ATP analogs for live cell applications, including kinase-catalyzed biotinylation.